CoAP
Definition
Constrained Application Protocol (RFC 7252). A RESTful protocol over UDP on port 5683 (or 5684 with DTLS), designed for constrained devices that cannot afford HTTP overhead. Supports GET/POST/PUT/DELETE on URI-style resources.
- Standard
- RFC 7252
- Transport
- UDP, port 5683 (5684 with DTLS)
- Style
- RESTful, URI-addressed resources
- Methods
- GET, POST, PUT, DELETE
- Target devices
- Constrained IoT devices
Common questions
Why do constrained IoT devices use CoAP instead of HTTP?+
CoAP's compact binary header and UDP transport need far less code space, memory, and power than HTTP over TCP/TLS, which matters on battery-powered sensors and low-power microcontrollers that cannot spare the resources for a full HTTP stack.
What does CoAP traffic reveal in an IoT forensic examination?+
Captured CoAP exchanges on port 5683 show which resources a device exposed and what requests were sent to it, giving investigators a record of device-to-device or device-to-hub commands even when no cloud service was involved.
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